In the last instalment we showed you how to take your flash off camera. Now, it’s time to take things a step further and modify the light.

To do this, we’re going to show you how to add impact to a portrait using a homemade GOBO.

GOBO stands for ‘go-between object’, and it’s simply a light modifier that goes between your light source and your subject. It can be a stencil cut to fit into your lighting, or it can be a freestanding object you’ve improvised for the job.

A GOBO can block the light, diffuse it or colour it. In this case we’re going to cut long rectangles in a sheet of card and place it in front of our flashgun (but not directly on the flashgun) to give the illusion that the light is passing through a blind.

We’re after a film noir feel here, but you can use a GOBO to create all sorts of lighting effects – and the principles are the same no matter what shape your GOBO is.

But what’s the best way to use a GOBO? And how should you set one up? Let’s take a look.

Step by step: To boldly GOBO...

Quick tip

You can make GOBOs from any material and in any shape. You could try making a rudimentary ring flash, for example.

1. Make the GOBO

To make the GOBO you’ll need a large sheet of card. Measure out and mark long rectangles about 2.5cm high by 60cm long, and space them about 2.5cm apart. Then take a scalpel or some scissors and cut the rectangles out. Use a steel rule to keep the cuts straight.

2. Set up the light

Attach your wireless receiver to the flashgun and mount it on a light stand, then place the flash camera-left, about two metres away from your model. Turn on the flashgun and receiver, and set the flash to 1/16 power. Attach the wireless transmitter to your camera’s hot shoe.

Reducing the power

If your flash is too bright, reduce the power to 1/32 or 1/64 until the image is correctly exposed and your highlights aren’t clipped. You can check this by looking at your histogram; if the graph is stacked up at the right, it’s clipped.

3. Set up the camera

We set the camera to f/8 in Aperture-priority mode, then adjusted our sensitivity to ISO 250, so that we had a shutter speed below 1/200sec (the sync speed of the flash). We then slowed it further, to 1/25sec, using exposure compensation, to let in more of the ambient light.

4. Position the GOBO

Take your GOBO and strap it to a light stand, or anything that stands upright, then set it up in front of the flashgun, about half a metre away, so it sits between the flash and the model. You can experiment with the position once you start shooting.

5. Direct the model

Don’t keep your model in one place – get them to move around. Ask them to look at the light and shift position so you can see how the light interacts with the contours of their face. The further your model is from the GOBO, the wider and more diffuse any shadows will be.

6. Add some atmosphere

You could combine this tutorial with some artificial fog to better define the shafts of light as they pass through the GOBO. You can also turn the final result black and white in software for that classic filmic effect.